CAIRO - U.N. envoy for Yemen Martin Griffiths is calling for the Saudi-led coalition and the Houthi militia group to respect the ceasefire that was agreed to Thursday, after a week of negotiations outside the Swedish capital Stockholm. A Houthi spokesman in Sana'a, however, says the cease-fire was not due to officially go into effect until Tuesday.

Pro-Houthi al-Maseera TV showed what it claimed was video of its fighters repulsing an attack on one of the group's positions near the Red Sea port of Hodeida. Scattered shelling and airstrikes have been reported around the city since a cease-fire was agreed to by both parties Thursday at U.N.-sponsored negotiations in Sweden.

Houthi spokesman Mohammed al-Bakhiti told Arab media Sunday the Saudi-led coalition and its allies continued to bomb Hodeida with field artillery and from the air and claims they have stepped up their attacks since Thursday.

A Houthi military spokesman in Sana'a Yahya Sarea said the ceasefire was due to go into effect Tuesday. He added ' [his group] hopes that [the Saudi coalition] will be true to their words, or else we are ready to respond.'

Arab media indicated the unarmed U.N. international observers would be deployed to monitor the cease-fire Monday around Hodeida.

Deputy minister for human rights in the internationally-recognized government, Nabil Abdel Hafidh, told Saudi-owned al-Arabiya TV Sunday the Houthis were 'stepping up their shelling of regions south of Hodeida' and the militia 'had not stopped attacking private property or looting facilities around the port for the past three days.'

He said the government of President Abdrabbu Mansour Hadi 'will respond if the Houthis fail to observe the cease-fire.'

Al-Mayadeen TV, which supports the Houthis, reported a Houthi leader in Sanaa called on the United Nations to 'make Saudi Crown Prince Mohammed Bin Salman and UAE Crown Prince Mohammed Bin Zayed observe the ceasefire.'

Arab and Western media also reported that informal discussions are still underway to initiate a prisoner release mechanism that was discussed last week at the talks in Sweden.

A resident of the divided city of Taiz, Wahib al-Biheiri, told al- Hurra TV he is optimistic his cousin, who has been held captive by the Houthis for nearly two years, will soon be released.

He says his cousin was stopped by Houthi militiamen at a checkpoint outside of Taiz as he was travelling on a bus from the capital Sana'a. He says they asked him questions about what he was doing and then detained him.

Both sides, together, hold around 15,000 prisoners. Each agreed in principle to release the captives it holds.